It is widely known that keyboards are used as input devices for computers, etc. It is known that keyboards can be adapted to transmit operation information of the keyboard by wireless means using an infrared ray signal, etc. In a wireless keyboard, a receiving unit on the computer such as an infrared ray receiving unit, etc. receives a signal transmitted from the wireless keyboard and executes processing that corresponds to the key operation information of the received signal.
There is a need to increase the kind of operations that a keyboard of limited size can handle. Measures to increase the use of many keys have been limited. In wireless keyboards, the simultaneous operation of about two to four keys is allowed at most. Simultaneous operations of more than two to four operations has heretofore been impossible.
An IR (Infra-Red) keyboard transmits operation information of a key by infrared rays. A transmit signal can be temporarily interrupted by any disturbance. For example, a human being or object passing between the light emitting unit of the infrared rays of the IR keyboard and the receiving unit. In such a case of disturbance, although key operation is successively carried out at the IR keyboard side, it is judged at the receiving side (e.g., computer side) that the key operation has been completed when the receive signal is cut off by interruption of the signal. This disturbance creates problems. For instance, interruption of the transmit signal, display, etc. of characters or ruled lines, etc. which have been inputted in accordance with the keyboard operation might uselessly overlap, or become missing or the like. So inconveniences are apt to take place wherein the computer of the receiving side fails to cope with the primary key operation that the keyboard user is carrying out.
In view of the above, an object of this invention is to provide an apparatus and method for transmitting signals from a wireless keyboard wherein said apparatus is capable of realizing a wide variety of key operation forms (modes) based on simultaneous operation of a large number of keys.
A further object of this invention is to provide an apparatus and method for transmitting signals from a wireless keyboard wherein there is less possibility of an erroneous operation because of an interruption of the transmit signal.